We plan to perform both laboratory and clinical studies. Our laboratory studies will be confined to experiments concerned with certain aspects of cholesterol metabolism. These will be as follows: (1) We shall investigate further the mechanisms at play in the neurogenic hypercholesterolemia we first produced and began to study in 1969. (2) We will explore the possibility that these may be receptors in the central nervous system (C.N.S.) sensitive to changes in the cholesterol content of plasma and that such changes in turn may influence the cholesterol level of the peripheral circulating blood. (3) We will continue to perfect our present methods of producing rats with severe hypercholesterolemia. (4) We will investigate the possibility that changes in the cholesterol content of plasma may alter th hormonal discharge of certain endocrine glands (pituitary, thyroid, and pancreas). Our clinical studies will be the following: (1) We propose to continue our measurement of the plasma content and also the rate and quantity of discharge of various steroid hormones in coronary prone (i.e. Type A behavior) and coronary resistant (Type B behavior) subjects. (2) We propose to continue our prospective study involving 150 post infarction patients in order to determine the respective prognostic value of clinical phenomena observed during their initial acute infarction. (3) We propose to collate the clinical and pathological data concerning a series of sudden cardiac death cases. The data are already at hand.